Note 11. Segment Information and Foreign Operations

Segment Information

We operate in one segment for the design, development, manufacture and distribution of high-performance compound and single element semiconductor substrates and sale of raw materials integral to these substrates. In accordance with ASC Topic 280, Segment Reporting, our chief operating decision-maker has been identified as our Chief Executive Officer, who reviews operating results to make decisions about allocating resources and assessing performance for the Company. Since we operate in one segment, all financial segment and product line information can be found in the condensed consolidated financial statements.

Product Information

The following table represents revenue amounts (in thousands) by product type:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
Product Type:
Substrates	$	21,603	$	19,109	$	40,967	$	35,718
Raw Materials and Others		5,517		4,448		10,572		8,455
Total	$	27,120	$	23,557	$	51,539	$	44,173

Geographical Information

The following table represents revenue amounts (in thousands) reported for products shipped to customers in the corresponding geographic region:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2018		2017		2018		2017
Geographical region:
China	$	8,820	$	6,324	$	16,003	$	10,746
Europe (primarily Germany)		6,685		5,848		13,078		11,446
Taiwan		4,280		4,195		9,329		7,513
Asia Pacific (excluding China, Taiwan and Japan)		2,571		2,645		4,065		4,716
Japan		2,524		2,862		4,979		6,002
North America (primarily the United States)		2,240		1,683		4,085		3,750
Total	$	27,120	$	23,557	$	51,539	$	44,173

Long-lived assets consist primarily of property, plant and equipment, and are attributed to the geographic location in which they are located. Long-lived assets, net of depreciation, by geographic region were as follows (in thousands):


	As of
	June 30,		December 31,
	2018		2017
Long-lived assets by geographic region, net of depreciation:
North America	$	853	$	1,410
China		64,321		45,120
	$	65,174	$	46,530

Significant Customers

No customer represented more than 10% of our revenue for the three months ended June 30, 2018 while two customers, Osram Opto and Landmark, represented 12% and 11% respectively, of our revenue for the three months ended June 30, 2017. Our top five customers, although not the same five customers for each period, represented 33% and 37% of our revenue for the three months ended June 30, 2018 and 2017, respectively.

Two customers, Osram Opto and Landmark, represented 11% and 10%, respectively, of our revenue for the six months ended June 30, 2018 while two customers, Osram Opto and Landmark, represented 11% and 10%, respectively, of our revenue for the six months ended June 30, 2017. Our top five customers, although not the same five customers for each period, represented 35% and 36% of our revenue for the six months ended June 30, 2018 and 2017, respectively.

We perform ongoing credit evaluations of our customers’ financial condition, and limit the amount of credit extended when deemed necessary, but generally do not require collateral. One customer accounted for 11% of our accounts receivable balance as of June 30, 2018, and the same customer accounted for 12% of our accounts receivable balance as of December 31, 2017.